Category: General

Fixing the brightness fluctuation problem on HP laptops with AMD graphics

After installing Windows 8 on my laptop for a second I decided not to install the AMD driver pack from HP website, since the driver that was installed by Windows Update worked perfectly and as you can imagine, I am not particularly fond of the oft-included management software that hogs system resources. Everything worked well until I discovered that when the computer is not plugged to the power, the screen brightness fluctuates widely – not following the ambient light as one would expect but according to the current content of the screen. Counterintuitively, the white windows in foreground made the screen turn brighter and vice versa, which made the problem even more visible.

I sifted through the power options (since this only happened when the computer was not plugged in), but I noted that the Adaptive brightness options were already disabled. I remembered having similar problems on my previous installation of Windows and as it turned out after a quick googling, this behaviour is caused by the ingenious feature of the AMD drivers, called Vari-Brightâ„¢ which can be easily turned off using the AMD’s Catalyst Control Center, which I chose not to install.

I figured that since the Catalyst Control Center is just a GUI frontend, the settings that are stored somewhere else, persumably in the registry. A bit of Google, a bit of trial and error and a couple restarts later, the brightness stayed constant.

I added a DWORD value PP_VariBrightFeatureEnable set to 0x00000000 to the following key:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0000

There is no need to install CCC just for this 🙂

The humble beginnings

After quite a long time of hesitation and indecisiveness, I have finally managed to get it together and start a blog. Despite having been active in the IT field for quite a while, I have never set up a place where I could unconstrainedly express myself, i.e. personal webpage, mostly for the reason that I have never really had anything to say to the masses. (well, I’ve been writing a Windows Longhorn beta testing blog for a while, but let’s just agree to never mention it again, shall we? ☺)

Well, things have changed. I have become more proactive in my fields of interest and during my technological meanderings, I have stumbled upon some interesting problems, figured out some interesting solutions and it would be a waste if I kept it all to myself and a small circle of my colleagues. I think that becoming active in the StackOverflow community helped towards this decision the most, because I have developed a habit of regular written expression, of whatever sort it may be. Hence, during my summer internship at Arnes, the idea of this blog was born et voilà, here it is. To the more fundamentalist of you: Yes, it is powered by WordPress and no, I am not ashamed. I find it quite exquisite thus far.

The content on this blog will probably revolve around topics that interest me most. Generally, you should expect some networking (routing software/hardware, IPv6 deployment and developments, …), some programming (C++11, alogrithms), and almost certainly some mathematics and linguistics. Occasionally I will (probably) drop in some non-technology, Real Life™ stuff. Maybe.

I guess that a promise that I will be posting regularly is in place but I consider this a bad omen. I hope it works out ☺.

Cheers, Tibor